Drying ap



7 March 8, 1932. v

' DRYING [APPARATUS J- B. WELCH Filed Jan 16, 1929 a Sheets-Sheet 1 l I I Jj yz.

Mal-ch48, 1932. t J. B. WELCH 1,848,811

DRYING APPARATUS Filed Jan, 1 1929 s Sheets-Sheet 2 March 8, 1932. J B. WELCH 1,348,311

' DRYING APPARATUS Filed Jan. 16, 1929 I5 Sheets-Sheet 3 INVENTOR WM BY Patented Mare 8, 1932 i I j mim Applicatien nle'd ianu r uef eze. j se' ai no. 332,835.:

i i This invention relates to iying apparatus and more particularly to a- -progressive dry kilnfor drying lumber;

The object of the mve'ntlonis toprovide '5 novel and improved dryingapparatus, and

particularly a" novel and improved progressive dry kilnfordrying-lumber; inwhi'ch provision is made for effectingboth longic tudinal'andcrosswise recirculation-of the air, within the kiln in a novel and improved) mannerwhereby increased eflicienc-y inlthe drying operation" may beobtained without disturbing the conditions'of temperature andhum-idity most" conducive-to most -rlficient drying, t g I! 3. i 'lo this endthe present iniprovedxprogres sive dry kiln isprovided-with means for sf fecting longitudinal recirculation of the air i the kiln is supportediupon the usual track' 1 p and the requisite'amount of humidity "may be 1 introduced" into the: kiln by admitting live Y within the kilnpreferably by mean's'j-of by-' pass conduits 1 througlr=which the heavier moist air sinks and isconductedinto'foneor more ducts-to be moved to the dry'end of the j kiln and thencejliberated under thelumber at the dryendi In order to maintain e'fiec'tive cross circulation-at either the-green or lth'e dry end "of the kiln, I or at both ends of the kiln, the present invention eontemplate's' the provision of air' ducts arranged to permit the air to-be circulated upwardly fromione duct and thence crosswise ofthe kilnand down-- wardly into another'duct, fThejductsare COD} 7 nected with an, air propelling device, #pref-f erably-ja blower, in a manner such; as to perg mit reversal of the crosswise circulationlwith- 1 out-necessitating reversal of the'lblower, and

in :this manner the system lends itself toithe use or standard-types of blowersdesi n d to operateinone'direction' only;-

I These and other" featu es of the invention;

will be hereinafter described and-.particw larly defined iii'i'the claims at the endqof specification. I g I In the drawings illustrating the preferred embodiment of the invention,;Fig. 1 is a vertical sectional elevation "of the green'en'd of a kiln embodying the present invention Flg; 2-

is a sectional plan of the portion ofthekiln- 7 shown in Fig. 1 and-Fig. 3 is a cross-section taken onthe line:3-;'-3..-ofvFig. 2;;Figsp4, 5$

and 6 show indetail, partly'insection,-the air closing such openings. I

from theidryto the green endgthereohvand as currentreversing mechanism for the bloweni i v the-air "as 'embodiedwin the green end ,ofa e kiln, it is to be understood that it' is not dee sired to limit the inventionto such construe 1 7 @011, In the-drawings the progressivedry I Q i it kiln is illustrative as comprising adrying chamber 10 through which the lumber tobe 6 dried isi passed. The chamber is provided 1 with-the usual openings Lat each end thereof,

one of which I is shown at 12, and through which the? lumber is introduced into and de liveredlfr'o'm the drying chamber. Suitable doors not shown are provided for normallyw "Thexlumber duringlits movement j steam from the several steam vjets :24 in the, manner 'now commonly practiced; The fair:

within the'chambe'r mayfbe 'heated any v novel or preferred means, the herein-shown.

- In the preferred embodiment of the inven tion provisiongis made for setting uplorigi tudinal recirculation-in the-air within thekiln herein shown the kiln is providedwith a pair of longitudinally extending ducts 30, 32 whichare/provideduat-the green end with bye pass. openings 36 through which, the: moist intotheends of the circulating ducts to? be carri ed through the ducts alongwith fresh; airadmitted through-the fresh .air inlet 5 pipes 38 to the dryend of theki ln wheretheairiis permitted to rise underthe lumber through a 1 series offopenings in: the surface of the lone.

1 gitudinal du'ctsr30, "32, the. cQnstructiOnbeing preferablyfthat illustrated in my Patent- No. 1,517,928.; From the dry end of the kiln longitudinal circulationofthe air takes" place through the body of the kiln back ate the green end. Asset forth in 'mypatentiabove referred to this system of developing the,

air; atxithergreen endinaysinkdownwardly longitudinal recirculation is basedwnponthe self-control recirculation of the air actuated primarily by diiierences in the density of two counter balancing columns of hot and cold air, and in the operation of the kiln the longitudinal recirculation is preferably maintained within such limits as to produce the desired drying conditions with respect to temperature and humidity. i V r In the practical operation of progressive dry kilns of the character described, in addition to the aforesaid longitudinalrecirculation of the air, it has been found desirable, to

provide crosswise circulation or recircula tion of the air either at the dry end, at the green end, or at both ends of the kiln, according to the particular conditions encountered in drying different types of lumber. .In accordance with the. present invention, novel and improved apparatus is provided for producing such crosswise recirculation of the air and in which the direction of movement of the air may be reversed without necessitating reversal of the blower or other air propelling means used. :As above stated, in the illustrated kiln provision is made for producing longitudinal recirculation of the, air at the green end of the kiln, and in which three air ducts 50, 51 and 52 are provided to extend from the green end of the kiln to a point sub.- stantially one-third of the length 01": the kiln. As illustrated two of the ducts 50, 51 maybe located at the sides of the kiln and'the remaining duct 52 located centrally of the kiln, so that during the operation of the kiln, air may be forced upwardly through suitable openings 53 in the surface of the central duct 52 and pass upwardly through the lumber and crosswisetoward each side of the kiln to be drawn down through suitable openings 57 intothe outer lateral ducts 50, 51, or in certain instances it may be desired to reverse this operation to cause the air .to pass up-, wardly from the outer lateral ducts 50, 51, and downwardly into the central duct 52. As herein shown, each outer duct 50,51 is connected by a transverse duct which is extended upwardly and is connected through an opening 60 in the end wall of the kiln with the end of a pivoted end section 61 of the dis charge pipe 62 of a blower 64:, sothat with the 'pivoted end section 61 in such a position movement of the air takespl'ace through the outer lateral ducts 50, 51 and upwardly into the kiln.. The central duct 52 is arranged to terminate in an opening 68in the end wall of the kiln in a position such that the pivoted end section 61 of the blower: discharge pipe 62 when swung into its lowered position may cooperate therewith to directithe air being discharged from the blower into the central duct 52 to cause itto move upwardly from the duct 52 and thence crosswise of the kiln and thence downwardly into the lateral ducts 50, 51, when it is desired to eflectcrosswise circulation in a reverse direction. 1 Both openings 60, 68 in the end wall of the kiln are connected with the suction side of the blower through a sheet metal conduit 72 which is provided with an offset portion 7 4:, as illustrated in Figs. 1 and 2.

A more detailed illustration of the selective operation of the blowerreversing arrangement is shown in Figs. 4, 5 and.6. In Figs and 5 the end section 61 is shown communic'ating with the opening 68 whereby the air is blown into the chamber through that opening. The air being sucked in from the chamber through the opening 60 will pass beneath the end section 61 and discharge pipe 62, thence through the bottom part of the opening 73 leading to the ofit's'et portion 74:

which leads to the suction side of the blower..

.to a raised position, it is possible to reverse the direction of c. crosswise ,recirculation of the air within the kiln, without necessitating reversal of the blower, thus permitting standard types of blowers to beutilized. In addition the blower a-ndits operating parts maybe located outside of the. kiln and in such a position are accessible for maintenance/ 2 .While it is preferred to utilize a standard type of blower for producing the air movement, it willbe understood'that other means may be used to produce such air movement, and while the preferred embodiment of the invention has been herein illustrated and described, it will be understood that the invention may be embodied in other forms within the scope of the following claims. Having thus. described the invention, what is claimed is v I I .;1. A progressive dry kiln comprising, a drying chamber provided with heating means, means for producing longitudinal circulation of drying air throughthe material in said chamber, a. duct system; within said chamber for producing crosswise circulation of the drying air therein, said system comprising outer ducts located near the side walls of said chamber, and a central duct between said outer ducts, a blower located outside said chamber for propelling circulating air through said ducts,means for connecting said outerducts with an opening in the end wall of said chamber, means for connecting said central duct to anotheropening in said chamber, and means for selectively connecting the discharge side of said external blower with either of said openings whereby the direction of the crosswise circulation may be reversed without reversal of said blower.

2. A progressive dry kiln, comprising a drying chamber provided 7 with heating means, means for producing longitudinal circulation of drying air through the material in said chamber, a duct system within said chamber for producing crosswise circulation of the drying air therein, said system comprising outer ducts located near the side walls of said chamber, and a central duct between said outer ducts, a blower located outside said chamber for propelling circulating air through said ducts, means for connecting said outer ducts with an opening inthe end wall of said chamber, means for connecting said central duct to another opening in said chamber, and a movable pipe section adapted to connect the discharge side of said blower with either of said openings, and means for con-- necting the other of said openings to the suction side of said blower, whereby the direction of crosswise circulation may be reversed without reversal of said blower.

In testimony whereof I have signed my,

name to this specification.

JOHN B. WELOH. 

